On back of index card: Symmetry: Evolutionary innovation: Key Cells and/or tissues:

Evolutionary Innovations Sponges – multi-cellularity Cnidarians (anemone) –radial symmetry/ tissues Platyhelminthes (flatworms) – bilateral symmetry – first hunters Nematoda (roundworms) – psuedocoelom Mollusca (snail) – true coelom Annelida (segmented worms) – true coelom/ segmentation Arthropoda – jointed appendages Echinoderms (sea stars) – deuterostome development/stem cells Chordates (bird) – deuterostome with complex central nervous system

Phylum Porifera

Porifera means “Pore-bearers” referring to the tiny openings in the animal. Simplest animals 2 cell layers separated by a gelatinous like substance (mesoglea, mesenchyme, mesophyl) Outer layer is pinacocytes Inner layer is choanocytes.

Support in a sponge Spongin – Flexible, protein Spicules – Hard structures made of Calcium or Silicon – Form a skeleton – Fossilizes well

How much deeper would the ocean be without sponges ? The flagella on the choanocytes, or collar cells, draw water into the sponge. Food particles are trapped in the choanocytes, collars, and taken into the cells by phagocytosis. Amoebocytes, carry the food to different parts of the sponge.

3 Body Plans – Asconoid –simplest, limited by SA:V ratio – Syconoid – includes folded walls – Leuconoid – most complex, folds upon folds, with branching canals

Sessile Asymmetrical Size: A few millimeters – 2 meters tall Reproduction – Asexual – budding – Sexual- hermaphrodites release gametes into water, they are taken in by neighboring sponges and trapped in the choanocytes. Fertilization occurs in the mesoglea

Classification – Some 9,000 species, only 150 are fresh water – Classes: Calcarea – all three body plans are represented though most are leuconoid. They are found in shallow waters, less than 100 meters deep (common in intertidal pools) They have a skeleton made of calcium carbonate spicules Why are these sponges small?

Classes cont’d: – Demospongiae – contains 95% of all sponge species. They are found at all depths from intertidal to the abyssal zones. All members have leuconoid body plans. Spicules are made from silica (1,2 or 4 rays) and spongin w/ Calcium base.

Classes cont’d: – Hexactinellida – “Glass sponges” are in deep waters 200 – 1000m deep (esp abundant in Antarctica). They can grow quite large and appear to have a vase or urn shape. The skeleton is made entirely of silica. Spicules have 3 rays. Syconoid and leuconoid.

Thought to be extinct for 100 million years…until2005 Three kinds of reef building glass sponges found in Canadian waters

Ecological Niche: – Filter feeders Some sponges can pump water 20,000 times their own volume in a day Trap bacteria (up to 90%) in water Glass sponges (Hexactinillids) are less efficient at trapping bacteria and prefer smaller pieces of organic matter The carnivorous exception: Some sponges in Class Demospongiae use spicules to trap crustaceans and digest them extracellularly Some harbor algae and cyanobacteria and derive nutrients from them.

Ecological Niche cont’d – Crab sponges supply housing for hermit crabs

Ecological niche cont’d: – The Pharmaceutical industry is creating a new niche for sponges. Anti-tumor, anti-cancer, anti-inflammatory, anti- rejection drugs – A glycolipid in Agelas mauritanus appears to recognize and boost natural killer T cells. – Study sponges for cell to cell recognition at grafting sites to understand tissue acceptance and tissue rejection.